Two converging technologiesoptical Imaging and fluorescent probes for cellular functionare revolutionizing the study of biological structure and the dynamics of chemical and genetic networks in living cells. The emphasis of the imaging facility is two-fold: imaging chemical and structural dynamics in intact cells and tissue, and resolving cell architecture at high spatial resolution. In live cells and tissue imaging, a key technology is two photon laser scanning microscopy (TPLSM). It minimizes phototoxic effects and offers the possibility to image deep into tissues. A set of instruments using this powerful technology Is available in the Imaging Facility. Until recently, ultra-structural studies could only be performed using Electron Microscopy (EM). The last few years have seen extraordinary developments of imaging techniques that are able to break the diffraction barrier by more than an order of magnitude. The advantages of optical microscopy over EM are numerous. A few examples are the possibility to label several targets with different fluorescent markers, and the compatibility with live imaging. Our facility now offers such an instrument and an increasing number of teams are interested in using it.